1. Field of Invention
The present invention relates to a gas generator used in a restraint system for a vehicle.
2. Description of the Related Art
Known gas generators used in restraint systems for vehicles include two combustion chambers. In such gas generators, two combustion chambers are defined by a tubular member or cup member arranged inside a housing.
Such a tubular member or cup member has a through-hole for discharging gas from the combustion chamber defined inside thereof to the outside. These through-holes are closed with a metallic adhesive tape to prevent a gas generating agent from leaking out before activation, and to increase to some extent the combustion pressure for the gas generating agent at combustion. The operation of affixing the adhesive tape over the through-holes requires positioning and is cumbersome. Furthermore, the adhesive strength of the adhesive tape may also deteriorate over time, which is likewise problematic.
FIG. 7A of U.S. Pat. No. 7,374,204 discloses an airbag inflator in which a first chamber 111 involves a second chamber 112. A gas outlet orifice 124b of the second chamber 112 is provided in a peripheral wall surface of a cup 110b which forms the second chamber 112, and the orifice 124 is closed with a cap 120b before activation. When the second chamber is activated, the cap 120b slides upwards to open the orifice 124b as shown in FIG. 7B. Note that, though it is described as “cup 110b”, the cup 110b is a cylinder rather than a cup in the drawings and by the function.
US-A 2007/008 5314 (equivalent to JP-A 2007-131 077) discloses a gas generator for an air bag, having, in FIGS. 2 and 4, a cup member 141, enhancer holes 134 and a cup-shaped thin film 147.